Blood Test May Give Early Warning on Heart Attack, Study Finds

March 21 (Bloomberg) -- A simple blood test may be able to
tell patients if they’re in imminent danger of having a heart
attack, a new study suggests.

Researchers compared blood samples of 50 heart attack
patients with 44 healthy volunteers, and found a much higher
level of abnormal circulating endothelial cells, or CECs,
according to the study, published today by the journal Science
Translational Medicine. Still, more study is needed before
doctors can say with confidence that these abnormal cells are
present before a heart attack occurs, said Barry Kaplan, vice
chairman of cardiology for North Shore University Hospital in
Manhasset, New York, who wasn’t involved in the study.

Endothelial cells line blood vessels and control the
ability of arteries and veins to widen and prevent clots. The
heart attack patients in the study had, on average, fivefold
more abnormally shaped versions of these cells, with multiple
nuclei, circulating in their blood than the healthy patients.

The discovery may tell doctors if someone has a crack or
plaque rupture in an artery, which can lead to clot formation
and heart attack, said Eric Topol, the study’s principal
investigator and director of Scripps Translational Science
Institute.

“Heart attacks only occur when this blood clot forms, and
cuts off the blood supply,” Topol said in a telephone
interview. “What this is about is catching it earlier than when
the blood clot forms.”

Timing Critical

Heart disease is the leading cause of death in the U.S.,
and more than 1 million Americans have a heart attack every
year, according to the U.S. Centers for Disease Control.

People often head to the hospital when they feel chest pain
or pressure, only to be sent home when doctors can’t detect a
problem with tests such as electrocardiograms, which measure
irregular heart beats and heart damage, Topol said.

If the findings can be validated, a blood test that can
take advantage of the discovery may be in use in hospitals as
early as a year later, he said.

Using this information as a predictor of imminent heart
attack may be premature, Kaplan said.

“They’ve identified that these abnormal circulating
endothelial cells are present at the time of plaque rupture --
the question is how far before plaque rupture are these cells
abnormal?” Kaplan said in a phone interview. “We don’t know
the answer to that based on this study.”

Current tests can only determine if a patient has a
severely blocked artery, or already has damage to the heart
muscle. Others with mild or moderate blockages often go
undiagnosed. As a cardiologist, Topol has had patients pass
stress tests only to have a heart attack weeks later.

Difficult Challenge

“It’s one of the most discouraging things you can have
happen as a cardiologist,” he said. “I’ve learned from this --
it’s important to inform patients that you can still have a
crack in your artery anytime -- we haven’t had a way to detect
that. Hopefully now we do.”

Further into the future, patients at risk could have a
nanosensor implanted in a vein to detect the abnormal cells and
then send an alert to a device.

“They would get a ringtone on their phone, saying you’re
going to be having a heart attack in the next week or two,”
Topol said.